EP 0245026 A2 19871111 - Optical heterodyne mixers providing image-frequency rejection.
Title (en)
Optical heterodyne mixers providing image-frequency rejection.
Title (de)
Optische Überlagerungsmischer mit Spiegelfrequenzunterdrückung.
Title (fr)
Mélangeur optique hétérodyne procurant une réjection des fréquences-images.
Publication
Application
Priority
US 86082586 A 19860508
Abstract (en)
The present invention relates to an optical heterodyne mixer providing image-frequency rejection which (a) detects a desired signal at frequency INTEGRAL L.O. +/- INTEGRAL IF while rejecting interference from any signal at the image frequency INTEGRAL L.O. +/- INTEGRAL IF, and (b) provides performance which is insensitive to fluctuations in the optical dimensions of the circuit. More particularly, the mixer receives both a local oscillator input signal and a received input signal comprising one or more optical signals, one of the input signals being linearly polarized and the other being circularly polarized. The two signals are merged by an optical device (30) and transmitted to a polarizing beam splitter (31) which has its polarization axes oriented at 45 degrees to the polarization direction of the linearly polarized signal. Each of the two beams from the polarizing beam splitter is detected by a separate photodetector (34, 35) and the resulting two currents from the two photodetectors are added by means of a 3 dB 90 degree IF coupler (38). One of the coupler outputs (39) provides the IF signal and the other coupler output (40) provides the IF signal of the image frequency.
IPC 1-7
IPC 8 full level
H04B 10/00 (2006.01); G02B 27/28 (2006.01); G02F 2/00 (2006.01); H04B 10/04 (2006.01); H04B 10/06 (2006.01); H04B 10/142 (2006.01); H04B 10/148 (2006.01); H04B 10/152 (2006.01)
CPC (source: EP US)
H04B 10/61 (2013.01 - EP US); H04B 10/614 (2013.01 - EP US); H04B 10/64 (2013.01 - EP US)
Designated contracting state (EPC)
DE FR GB IT
DOCDB simple family (publication)
EP 0245026 A2 19871111; EP 0245026 A3 19890607; EP 0245026 B1 19930707; CA 1256501 A 19890627; DE 3786418 D1 19930812; DE 3786418 T2 19931021; JP S62272234 A 19871126; US 4723317 A 19880202
DOCDB simple family (application)
EP 87303853 A 19870430; CA 535969 A 19870429; DE 3786418 T 19870430; JP 11093187 A 19870508; US 86082586 A 19860508